Tactile and gustatory nerve fibers often respond not only to mechanical and chemical stimulation respectively, but also to thermal stimulation; what this imperfect stimulus selectivity at the physiological level might imply concerning the way things actually feel and taste constitutes the main objective of this proposal. Extensive pilot work in this laboratory has shown that temperature can often profoundly intensity the perceived magnitude of touch and taste sensations. We propose to enlist psychophysical methods, especially magnitude estimation, to deepen our knowledge about such sensory interactions and permit us to specify quantitatively how temperature combines with mechanical and chemical stimulation to arouse various levels of touch and taste magnitude. In the tactile domain, we plan experiments to try to separate out possible peripheral versus central interactions, to learn why interactions take place more readily in some body regions than in others, to learn what effect thermal adaptation has on touch intensification, and to learn whether temperature can also intensify vibrotactile sensations of low and high frequencies. In the gustatory domain, we will measure the effects of a wide range of temperatures on the taste magnitude and quality of a wide range of concentrations of sucrose, NaCl, quinine hydrochloride, citric acid, monosodium glutamate, and 5' sodium guanylate.